Lion and Macs with 4GBs of RAM (or even 8GBs)

There is a consistent theme in various Apple Support Communities, here, and in other hardware and software communities

People with Macs which have 4GBs of RAM are asking, "Why is my Mac so slow under Lion, when it worked fine with Snow Leopard?"

I have suggestions for you if you are considering upgrading to Lion, no matter how much RAM you have, but especially if you have 4GBs or less. Lion uses more RAM, and this may hurt your performance after the move to Lion. You need to plan for this

Check Activity Monitor for Page Outs after you have been using your Mac normally for some hours. If Page Outs are zero or very close to zero, then you'll probably be happy with Lion

If Page Outs are not zero, identify your most commonly used apps which are significant consumers of RAM, and change them so that they run in 32 bit mode, not 64 bits, then reboot

Again, check Activity Monitor for Page Outs after you have been using your Mac normally for some hours. If Page Outs are zero or very close to zero, then you'll probably be happy with Lion

If you are still getting Page Outs, then try running fewer apps concurrently, but only if you can live with this compromise

If you still haven't reduced Page Outs to almost zero, then either stay with Snow Leopard, or upgrade your RAM

FAQ

How do I change an app to 32 bit mode?

Go to your Applications folder, find the app, select it and press Command-i

A window will open titled "applicationname Info" and about half way down you should see "Open in 32-bit mode" with a checkbox beside it. Check it.

If it doesn't say that, then look in this window for "Kind". If it says "Application (PowerPC)", then you have another issue to resolve before upgrading to Lion, because this app will not work under Lion.

How much RAM is enough? And how much time should I spend agonizing over how much to get?

RAM is cheap, so if you don't want to spend a lot of time in decision-making, just add at least 4GBs if it will fit, or 8GBs if you plan to keep the Mac for a while, or bite the bullet and just max it out, unless that would be just too expensive.

If the budget is tight, or the Mac is an older one with limits on RAM, consider 2 GBs an absolute minimum upgrade

Why should I change the apps to 32 bit mode? Why can't Apple "fix this problem" for me?

64 bit mode was introduced to allow apps to exploit large memories. Your Mac is not a large memory Mac. This is not a problem to be fixed by Apple. Use the app in 32 bit mode on a small memory Mac.

But Apple says that Lion needs only 2GBs to work! What's going on here?

It is true that Lion will work in 2GBs. It is not necessarily true that the experience will be enjoyable, unless you run apps which have low RAM demand and run few of them. For example, if you just wanted to run TextEdit alone on a 2GB Mac, you'd probably get great performance under Lion. It's marketing-speak. If you ask me, I'd say that 8GBs is the smallest realistic RAM size for Lion if you prefer a hassle-free experience, and if you can get more, do it.

Why is Lion using up more RAM, this sounds like it is less efficient than Snow Leopard, isn't it?

New releases of operating systems always use more RAM. Why? To save I/Os, to save you time, and to fit new function into your system. Because RAM is cheap and getting cheaper all the time, OS designers are always looking for ways to use more RAM if it will provide a benefit to the end user. What they are doing is optimizing expensive resources, like your CPU, and HDD accesses. And your time! RAM is not an exensive resource.

Lion actually uses less RAM than Snow Leopard because it has a more efficient virtual memory system. I agree that 4 GB is the minimum one should use, but there is nothing about Lion that will cause it to run poorly on only 4 GB. Lion runs great on my 4 GB machine. The few issues I have are not RAM related.

I disagree with your assessment. I certainly wouldn't want to use a 2GB system with Lion - I tried it and found I could run one program and a couple little utilities like LaunchBar and EverNote without PageOuts becoming an issue. I certainly couldn't run Lion the way I like to with 2GB. But 4 GB is what my office computer has and I've regularly run Word, Safari, Filemaker Pro, Mail, BusyCal, and several utilitiy programs and noticed no difference from Snow Leopard.

Would I rather use a computer with 8GB or more? Yes, because I like to launch my apps and have them ready when I want them rather than wait for Photoshop or Excel to load. So on my notebook I typically have 10-12 applications running - as well as my utilities like LaunchBar, EverNote, etc. 8GB lets me do this comfortably, with 4GB I'd see a lot of pageouts.

If a user's computer is slow under Lion but wasn't with Snow Leopard, before adding more RAM, the first thing to do is make sure the user has a solid Lion installation. The upgrade method Apple has chosen to use leaves too many incompatible (not crashing incompatible, mind you, just not Lion ready) plug-ins, services, contextual menus, etc. Get that taken care of, make sure the user has up-to-date software and drivers and often that slow Lion computer has begun to purr. And frankly, sometimes the only solution is to erase the drive and install Lion on an empty drive.

I should clarify. I wasn't saying that Lion won't work in 4GBs. Just that it's worth looking at.

I was saying that people with 4GBs have complained about performance issues. Not all people, just some disappointed ones. Since this has been a consistent theme, what I am saying is that there are warning bells there. But clearly, the mileage varies. Some are very satisfied with the behavior of a 4GB Mac with Lion. Others are not, and my objective was to provide readers with a method of avoiding unpleasant surprises.

I went on to make a general recommendation for those who "are considering upgrading to Lion, no matter how much RAM you have, but especially if you have 4GBs or less"

And that led on to a method of assessment, which in steps 1 and 3 identifies situations in which Lion is likely to work fine, even if the Mac has 4GBs or even less.

The important thing in the post is the method of assessment. If you, the reader, have a small RAM Mac, and this method works for you, helping you avoid a bad experience or giving you justified confidence to proceed, then my goal has been achieved.

I'll throw my $.02 into the wishing well and say that I installed Lion on my early-2011 15" MBP and was not dissatisfied with the performance one Spotlight finished it's initial indexing. The OS was stable and fast for me in 4 GB of RAM. I did upgrade to 8 GB because I needed more RAM for Aperture, which is a really hog, and I have seen a general improvement overall with double the RAM, but if I had not been running Aperture all the time I would have been happy with the original 4 GB.

Why do new Macs only have 4GB then? Adding another 4GB or more by ordering from Apple Store is very expensive. I thinkt that the basic configuration should have 8GB when delivered with Lion.

If 64 bit mode is not for small computers, wouldn't be better that the system automatically uses 32 bit mode for most applications? Or alternatively, have an option for this instead of that the use shall downgrade manually for each large application.

Why do new Macs only have 4GB then? Adding another 4GB or more by ordering from Apple Store is very expensive. I thinkt that the basic configuration should have 8GB when delivered with Lion.

If 64 bit mode is not for small computers, wouldn't be better that the system automatically uses 32 bit mode for most applications? Or alternatively, have an option for this instead of that the use shall downgrade manually for each large application.

Hans

They offer 4GB Macs because for many, 4GBs is enough. Your mileage may vary! For me, 4GBs is not enough in Snow Leopard, let alone Lion. And certainly, Apple's RAM pricing is unattractive, so we buy the RAM upgrades elsewhere.

On the 32 vs 64 issue, it's all a matter of choice, and the cutoff point between when 32 bit is better than 64 bit is not at some magic number, it's a grey area. Again, what works for one person's application mix and workflow may not work for another.

Choice is important, you may choose to allow your favorite app to run in 64 bit mode, and limit all the other apps.

The good news is that you have probably only got a handful of apps to change the settings on and then it's done.

In a few years time, we will all be exclusively on 64 bit apps. How many 8 bit apps do you still run?

People with Macs which have 4GBs of RAM are asking, "Why is my Mac so slow under Lion, when it worked fine with Snow Leopard?"

John- My Mac has 4gb of RAM. It's a mid-2007 20" iMac 2.4ghz Core2Duo, and while not at the very bottom of the compatibility list, it's bringing up the rear.

The first couple of hours after I upgraded to Lion over Snow Leopard, it was very slow and was running hot. This was due to the Spotlight indexing.

It was better after the indexing was complete, but was still noticeably slower for the next several days. After that, it was fine and now runs as fast or faster than it did under Snow Leopard. I don't know why; I think there might be some Versions background process which chums the processor until its initial "indexing" or whatever it's doing is complete.

I think all the statements in your OP are helpful to new upgraders, but I'm hearing many reports similar to mine. So in addition to all you said, I'll add: Give your new Lion time to settle in to its home, especially if you recently evicted a Snow Leopard from the same space. After a few days it will purr along just as well or better than the old cat.

<snip> I think all the statements in your OP are helpful to new upgraders <snip> I'll add: Give your new Lion time to settle in to its home, especially if you recently evicted a Snow Leopard from the same space. After a few days it will purr along just as well or better than the old cat.

John,

My target audience is the would-be new upgrader who wants help in deciding what to do.

I'm glad you had success, maybe it's because of those housekeeping things that OS X does in the middle of the night. I have heard it moves stuff around to optimize things. I left my MBP on for many nights with the expectation that OS X might do good things while I slept.

I have no idea if it happened, but my MBP with 8GBs seems to work just as fast under Lion as it did under Snow Leopard

I upgraded the RAM on my 21.5" iMac (10,1) from 4 to 12Gb, using SO-DIMM sticks bought from an eBay seller at a cost of less than £100, and installed by myself. It has made a huge difference to the way Lion runs on that machine.

That said, my 11" MBA has only 2Gb, and yet it too runs very quickly under Lion - I haven't noticed any difference from SL. Clearly I am doing less on that machine, but even doing the same things (browsing with FireFox, word processing with Word and Pages), the Air seems as snappy as the iMac.

Why should I change the apps to 32 bit mode? Why can't Apple "fix this problem" for me?

64 bit mode was introduced to allow apps to exploit large memories. Your Mac is not a large memory Mac. This is not a problem to be fixed by Apple. Use the app in 32 bit mode on a small memory Mac.

Sorry mate, I appreciate the hints, and I'll try to switch Safari to 32 bits. But this IS a problem it must be fixed by Apple (or Adobe?). Safari or Flash and probably the whole virtual memory management system is bugged. Otherwise someone should explain me why, still having 1GB of inactive memory, just watching youtube videos suddendly my virtual memory went from 0 to about 1GB or so. Obviously slowing down the system drammatically because paging out. And why closing and restarting Safari, reopening the old session the virtual memory decreased to 204MB giving me 1.34GB of free RAM.

Thomas, my guess is that your MBA is paging a lot since it has only 2GBs. Take a look at Page Outs. However, the MBA is paging to and from an SSD, which is an order of magnitude faster than a HDD, so it can tolerate the paging, at least to a degree.

Back in the 80s, we used to instal SSDs on mainframes which had limited RAM. The SSDs were only used for paging. This extended the life of the mainframe CPUs significantly, and allowed more effective utilization.

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